Tubular goods, whose use includes, but is not limited to, use in drilling for, and production of oil and gas, experience a considerable amount of handling and a certain degree of mishandling and abuse on their journey from the steel mill to the final well destination. As a result, screw on cylindrical thread protectors, with a full compliment of threads, are placed on such tubular goods to protect the threads from any harm prior to installation. However, because the removal of such protectors often requires an expenditure of time that cannot be tolerated during the installation of tubular strings in wells, the original protector is often removed at the well site and is replaced with a different protector with quick release and installation capabilities. The tubular good subsequently rides from rack to rig with the new thread protector, which is eventually removed when the joint is to be threadedly attached to the downwardly continuing string. During the interval that the protector is on the threads, a last bore drift test is usually done, and it is desirable that the protector does not interfere with the drift passage. Once the string is pulled out of the hole, the quick install capabilities of such a thread protector ensure protection for the threads on tubular goods whose threads have not been damaged in the drilling activity.
A considerable amount of development work has been done in efforts to improve the bands and related tensioning gear to keep the casing protectors from being knocked off the threads during the rack to well trip.
The body of protectors in rig site use are currently made of elastomer, sometimes polyurethane, but may sometimes be made of other material, such as black rubber. The elastomer is formulated and cured to serve the skid and bash protection function and does not always favor thread gripping. In order for the elastomer to adequately grip the threads on the tubular goods to be protected, a sufficient amount of hoop force must be applied, which is often accomplished through the tensioning of bands around the elastomer. However, such securing bands are designed to be tensioned by hand and consequently, seldom have enough energy to drive the elastomer into the thread grooves sufficiently to prevent the occasional slipping of the protector.
Furthermore, the thread protectors on the rig site are currently designed so that the elastomer is pulled apart to accommodate the threads to be protected and subsequently tightened around such threads when the protector is in place. The net effect of repetitive pulling apart is that the elastomer would eventually deform due to the repetitive yielding, causing the elastomer to lose its memory characteristics.
There have been many attempts in this art to provide improved protectors for male threads on the pin end of oilfield tubulars. U.S. Pat. No. 5,524,672 to Mosing, et al, and U.S. Pat. No. 5,819,805 to Mosing, et al, each having been assigned to Frank's Casing Crew and Rental Tools, Inc., are two such prior art patents. The prior art has typically used components which are in intimate contact with the male threads, and while they oftentimes have been used with a great deal of success, these components have sometimes failed to protect the threads when the tubular is dropped or banged against hard surfaces, such as rig floors of ramps and truck bodies. This is especially true when such prior art protectors are used with two-step threaded oilfield tubulars having premium threads.
U.S. Pat. No. 5,706,894 to Samuel P. Hawkins, assigned to Frank's International, Inc., the assignee of this present invention, shows a device for suspending various downhole tools below the device, for repair and maintenance purposes. Moreover, there have been many attempts to provide lifting surface on the exterior of smooth surfaced oilfield tubulars to which elevators can be attached to either raise, lower, or otherwise move said oilfield tubulars.
U.S. Patent Application No. 2012/0061528 discloses a gripping device for engaging a tubular with a collet structure to receive a tubular. The collet has a plurality of elongated blades, with each blade having a gripping structure at the unsupported end. Because the device requires a gripping surface to establish resistance, the device will not work with tubulars (e.g., casing) that has a tapered or swaged connection or tubulars (e.g., casing) that has an integral box end. Such upset tubulars or casing therefore comprise varying diameters, which are not controlled generally by the American Petroleum Institutes' specifications; and as such, it is difficult to design and engineer a gripping device(s) and/or a gripping surface(s) that can handle one or more of the varying upsets of the tubulars. In addition, sufficient frictional forces are required in order to enable a gripping surface to work; however, if the frictional forces are too high (e.g., intense), then the intense frictional force can cause damage to the tubulars. Accordingly, there is a need for a load ring lifting device that can be suitable for casing or upset tubulars, which have a tapered or swaged end or connection, and/or include an integral box end. In addition, there is a need for a load ring lifting device that does not require the use of intense frictional forces for forming a gripping surface. The embodiments of this invention satisfy these needs.
The objects, features and advantages of this invention will be apparent to those skilled in this art from a consideration of this specification, including the attached claims, the included Abstract, and the appended drawings.